Aspects to Take into Account in the Design ofUltrasonic Angiological Doppler Equipment

Some of the main causes for which electrical noise is generated in ultrasonic angiological Doppler equipment are presented, mentioning their origins and characteristics. These can be of internal or external origin to the equipment, degrading their operation. The values of the impedance and phase module, corresponding to six Doppler sensors, and their incidence in the noisy behavior, according to the inductive or capacitive value of the impedance module for each one, are shown.In addition, the relationship between the bandwidth of the Analog Block’s receiver and the amplitude deformation (spectral composition) that occurs when the equipment operates in the pulsed mode of the Doppler signal is highlighted. Finally, it is presented as a compromise condition: "the lower bandwidth that guarantees the lower noise power at the output of the Analog Block’s receiver and at the same time, achieve the lowest deformation produced in the envelope of the pulse". Some additional recommendations are also suggested to mitigate noise.